Broadband bandpass filter and filtering power divider with enhanced slow-wave effect, compact size, and wide stopband based on butterfly-shaped spoof SPPs

Purpose The purpose of this paper is to present the design of a compact microstrip bandpass filter (BPF) in dual-mode configuration loaded with cross-loop and square ring slots on a square patch resonator for C-band applications. Design/methodology/approach In the proposed design, the dual-mode response for the filter is realized with two transmission zeros (TZs) by the insertion of a perturbation element at the diagonal corner of the square patch resonator with orthogonal feed lines. Such TZs at the edges of the passband result in better selectivity for the proposed BPF. Moreover, the cross-loop and square ring slots are etched on a square patch resonator to obtain a miniaturized BPF. Findings The proposed dual-mode microstrip filter fabricated in RT/duroid 6010 substrate using PCB technology has a measured minimum insertion loss of 1.8 dB and return loss better than 24.5 dB with a fractional bandwidth (FBW) of 6.9%. A compact size of 7.35 × 7.35 mm2 is achieved for the slotted patch resonator-based dual-mode BPF at the center frequency of 4.76 GHz. As compared with the conventional square patch resonator, a size reduction of 61% is achieved with the proposed slotted design. The feasibility of the filter design is confirmed by the good agreement between the measured and simulated responses. The performance of the proposed filter structure is compared with other dual-mode filter works. Originality/value In the proposed work, a compact dual-mode BPF is reported with slotted structures. The conventional square patch resonator is deployed with cross-loop and square ring slots to design a dual-mode filter with a square perturbation element at its diagonal corner. The proposed filter exhibits compact size and favorable performance compared to other dual-mode filter works reported in literature. The aforementioned design of the dual-mode BPF at 4.76 GHz is suitable for applications in the lower part of the C-band.

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A Wideband Bandpass Filter Integrated Single-Pole Double-Throw Switch with Wide Stopband

Frequenz ◽

10.1515/freq-2018-0045 ◽

2018 ◽

Vol 72 (11-12) ◽

pp. 533-537 ◽

Cited By ~ 1

Author(s):

Jin Xu ◽

Qi-Hang Cai ◽

Zhi-Yu Chen

Keyword(s):

Insertion Loss ◽

Bandpass Filter ◽

Fractional Bandwidth ◽

Central Frequency ◽

Resonant Frequencies ◽

Capacitively Coupled ◽

Filter Theory ◽

Compact Size ◽

Better Than ◽

Coupled Resonator

Abstract This paper proposes a wideband bandpass filter (BPF) integrated single-pole double-throw (SPDT) switch by using the capacitively coupled LC resonators with loaded p-i-n diodes. The BPF-integrated on-state channel can be synthesized by using the coupled resonator filter theory, and the off-state channel with high suppression is built due to the misaligned resonant frequencies of LC resonators. As an example, a BPF-integrated SPDT switch is designed and fabricated with the central frequency of 1 GHz and the 3 dB fractional bandwidth of 29.7 %. The on-state channel has a measured insertion loss of 1.23 dB, and a 20 dB rejection wide stopband from 1.47 GHz to 8.6 GHz. The off state channel has a 43 dB suppression around 1 GHz. The isolation between two ports is better than 52.4 dB. The fabricated BPF-integrated SPDT switch size including bias circuits but excluding feeding lines has a compact size of 0.086 λg×0.096 λg.

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Compact bandpass-filtering response power divider with high-frequency selectivity and high isolation

International Journal of Microwave and Wireless Technologies ◽

10.1017/s1759078718001654 ◽

2019 ◽

Vol 11 (08) ◽

pp. 755-760

Author(s):

Jiawei Li ◽

Kaijun Song ◽

Fei Xia ◽

Shema Richard Patience ◽

Song Guo ◽

...

Keyword(s):

Slow Wave ◽

High Frequency ◽

Reasonable Agreement ◽

Frequency Selectivity ◽

Power Divider ◽

Dual Mode ◽

High Isolation ◽

Wave Characteristics ◽

Capacitive Load

AbstractA compact high-isolation power divider with bandpass response and high-frequency selectivity is presented in this letter. Two dual-mode resonators are used to realize filtering response. The circuit size of the proposed power divider can be reduced by using dual-mode capacitance loaded square meander loop resonators. Due to capacitive load, the resonator can exhibit slow-wave characteristics, which can be utilized to suppress harmonics and reduce size. The simulated and measured results show reasonable agreement.

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